C3P0 半开连接关闭

Question

在我的应用程序中，我使用 C3P0 连接到数据库服务器。这里的数据库服务器在防火墙后面运行。

防火墙有时会因 TCP 连接变得半开而出现异常，C3P0 认为这些是有效连接并尝试触发查询。 C3P0 辅助线程正在接受这些半开放的查询，而应用程序线程正急需连接。

`"com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1" daemon prio=10 tid=0x00007fec0865d000 nid=0xc1fe runnable [0x00007fec4cb66000]
       java.lang.Thread.State: RUNNABLE
        at java.net.SocketInputStream.socketRead0(Native Method)
        at java.net.SocketInputStream.read(SocketInputStream.java:152)
        at java.net.SocketInputStream.read(SocketInputStream.java:122)
        at com.ingres.gcf.dam.IoBuff.fillBuffer(Unknown Source)
        at com.ingres.gcf.dam.IoBuff.next(Unknown Source)
        - locked <0x0000000782455468> (a com.ingres.gcf.dam.InBuff)
        at com.ingres.gcf.dam.InBuff.receive(Unknown Source)
        at com.ingres.gcf.dam.MsgIn.receive(Unknown Source)
        at com.ingres.gcf.dam.MsgConn.receive(Unknown Source)
        at com.ingres.gcf.jdbc.DrvObj.readResults(Unknown Source)
        at com.ingres.gcf.jdbc.JdbcConn.connect(Unknown Source)
        at com.ingres.gcf.jdbc.JdbcConn.<init>(Unknown Source)
        at com.ingres.gcf.jdbc.JdbcDrv.connect(Unknown Source)
        at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:81)
        - locked <0x0000000780025b10> (a com.mchange.v2.c3p0.DriverManagerDataSource)
        at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:96)
        - locked <0x0000000780025b70> (a com.mchange.v2.c3p0.WrapperConnectionPoolDataSource)
        at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.acquireResource(C3P0PooledConnectionPool.java:89)
        at com.mchange.v2.resourcepool.BasicResourcePool.acquireUntil(BasicResourcePool.java:665)
        at com.mchange.v2.resourcepool.BasicResourcePool.access0(BasicResourcePool.java:32)
        at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1206)
        at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:368)
    `

是否有任何解决方法可以克服这种情况？

使用的数据库是VECTORWISE数据库

Answer 1

如果套接字读取，从应用程序的角度来看，无限期挂起——既不成功也不失败 Exception——c3p0 唯一真正能做的就是暂停它们并尝试打断他们。

您上面显示的失败不是在查询中，而是在 Connection 获取中。您可以尝试设置 maxAdministrativeTaskTime to time this out. Obviously, if c3p0 can't fetch Connections, attempts to use your DataSource will still fail. But they should (eventually, after a lot of timeouts, see acquireRetryAttempts and acquireRetryDelay) 显式中断，使用 Exceptions 给客户端，而不是永远等待

（这取决于挂起对 Thread.interrupt() 的敏感性。如果不能被打断 maxAdministrativeTaskTime 也无济于事。）

C3P0 半开连接关闭

C3P0 half open connections closing

connection

tcp

c3p0

detection